The present invention relates to portable light systems and more particularly to a compact, portable, self-contained light system for enclosures.
The electrical lighting of enclosed spaces such as auditoriums began with arc lamps powered by either storage batteries or by dynomotors. These low resistance, high current devices gave a harsh light dramatically different from the gas or oil lamps then in general use, and required heavy connective wiring due to their high current use. Also, because of the high current requirements and associated high power losses in the connective wiring, the power source was located in close proximity to the arc-lamp(s). Thomas Edison created a high resistance, incandescent lamp that gave a “soft” light similar to that of a gas lamp. Because the lamp resistance was high, the current requirement was low thereby allowing power to be conducted over a much greater distance to the lamp without significant power loss. Edison's lamp made the lighting of homes practical and he enjoyed considerable commercial success. While Edison's incandescent lamp had real advantages over arc lamps, the incandescent lamp still generated significant heat. Although the heat generated could, in some cases, cause problems, the greater significance of the heat was that it represented power consumption which did not result in light generation. Incandescent lamps have relatively low efficiency. The introduction of fluorescent lamps was a dramatic breakthrough for the lighting industry. Fluorescent lamps are more efficient, do not generate significant heat, and therefore are able to produce equivalent light to a given incandescent lamp at much lower power. Most large interior spaces are now lit by fluorescent lamps because of these advantages.
Small interior spaces, such as closets, cabinets, or other enclosed storage areas are frequently lit by battery powered devices. In large enclosures such as closets and storage areas the size of even a large battery-powered light is small compared to the interior space of the enclosure. Numerous devices exist for such applications. The lighting of small enclosures requires that the lighting device be sufficiently small to not adversely affect enclosure function. The requirement for small size in a battery-powered lighting device conflicts with the requirement for sufficient light generation for a useful length of time. Increasing the power and energy requirements (illumination output and time) increases the size of the battery required, which increases the size of the device. The battery size and therefore the device size are also determined by the efficiency of the lamp. A lamp which is inefficient, that is, one in which a large portion of the power supplied produces heat rather than light, will require a relatively larger battery than a more efficient lamp for a given application. Because of this, numerous improvements have been made in the efficiency of miniature incandescent lamps. Their best efficiency, however, is inferior to that of Light Emitting Diodes (LEDs), more recently developed electronic devices which emit light. Early LEDs had high efficiency but low light output. Recently developed LEDs have high light output and high efficiency making them suited for many applications in which incandescent lamps were previously or are currently used. This combination of high light output, and high efficiency also enables the creation of devices with performance characteristics unattainable using incandescent lamps. It is possible to create devices which have small size, high light output and acceptably long battery life for many applications. LEDs offer many of the advantages for low-voltage lighting that fluorescent lamps offer for higher-voltage, alternating current lighting. The impact of LEDs on the lighting of small enclosed spaces is likely to be similar to that of fluorescent lamps on the lighting of large enclosed spaces.
Battery technology has also improved. Alkaline batteries were an improvement over dry-cell batteries in that they were able to produce up to 85% of original performance after five years of storage, however, voltage drops off significantly during use. Many alkaline batteries are discarded with 50% of their potential energy unused. More recently developed silver-oxide and lithium-manganese batteries have higher energy densities and maintain a nearly constant voltage over their usage life. Together these characteristics make possible the manufacture of small batteries whose performance matches that of much larger alkaline batteries. The result is the button and coin batteries used in watches, cameras, calculators, and small illumination devices such as key-chain lights.
The lighting of small, portable or fixed enclosures is frequently problematic in that the lighting system often must have its own power source, and must be of a size which will not occupy an unacceptably large portion of the enclosure or interfere with the function of the enclosure. Typical of such fixed enclosures are, for instance, electrical boxes, cabinets, mail boxes, lockers, or freezers. Some of these fixed enclosures may be on a boat, RV, truck or automobile. Typical of portable enclosures are fishing tackle boxes, tool boxes, coolers or storage boxes. It is frequently desirable that the lighting device interact with the enclosure door so that the device is activated when the enclosure is opened, and deactivated when the enclosure is closed. The amount of light produced must be sufficient to illuminate the interior of the enclosure, and the battery must contain sufficient potential energy to give this usable level of light for a practically useful period of time. Additionally, an enclosure may not be opened for an extended period of time during which the lighting system may be exposed to humid air, or even corrosive atmospheres as in the case of enclosures on boats or those exposed to weather.
A number of prior art devices exist. U.S. Pat. No. 4,414,611 by Seltzer, et al, teaches a portable light for enclosures which may be powered by batteries contained within the device, or from an external low-voltage energy source such as a car battery. The device as described is unacceptably large for lighting small enclosures and is not sealed, making it unsuited for the lighting of enclosures exposed to weather or humidity due to likely corrosion. Activation is by a switch. There is no provision for automatic activation by an enclosure door.
U.S. Pat. No. 4,442,478 by Stansbury teaches an automatically actuated enclosure light suitable for drawers and automotive glove boxes. The device has a unique mechanism for activation by relative movement between an enclosure surface and the light, but does not have a separate manual means for activation. The unit is not sealed making it suitable only for enclosures having a controlled environment to prevent corrosion of the mechanism, circuitry and batteries.
U.S. Pat. No. 4,754,376 by Winslow teaches a specialized, demountable enclosure light for ice chests. The battery powered device mounts to the lid of an ice chest. A switching means allows the light to be on, off or activated by a position-sensing switch. If activation by the position sensing switch is selected, opening the lid causes the light to activate. The light described would be useful for lighting other enclosures having doors with a horizontal hinge, however, the light as described has multiple sites through which liquid and or water vapor can enter the device and corrode internal components.
The self-contained lighting apparatus taught in U.S. Pat. No. 4,755,915 by Rogers has a positioning sensing switch which activates when the assembly is tilted. The device is well suited to use in enclosures which have a horizontally hinged door such as mailboxes. The only means of activation is the position sensing switch. There is no means for overriding the positional activation so that the enclosure can be open for an extended period of time without draining the batteries. The life of the device is likely to be limited by corroding of internal components due to exposure to humidity of the surrounding air.
Herman, in U.S. Pat. No. 5,685,630 teaches a “Battery-Operated Automatically Switched Lighting Device” for the illumination of enclosures provided with doors. The device is designed to be producible at low cost. Activation is by a formed metal strip which protrudes from the housing of the device. When the strip is depressed, as by contact with the closed door of an enclosure to which the device is attached, the light is deactivated. Releasing the strip, as by opening an enclosure door, activates the light. No means is provided for overriding the activation so that an enclosure can be kept open for an extended period of time without draining the batteries. The device is well suited to use in fixed enclosures that are protected from humid air which would tend to corrode components.
Plunger activated enclosure lights are taught by Canfield in U.S. Pat. No. 5,032,957 and Burke in U.S. Pat. No. 6,033,084, the latter being intended for use in mailboxes. When the plunger is depressed as by the door of an enclosure the light is deactivated. Releasing the plunger as by opening a door activates the light. The Canfield device can be manually activated by an external switch as well as the plunger. Plunger devices are difficult to seal making them susceptible to corrosion of their components.
Brothers in U.S. Pat. No. 5,975,713 teaches a light for illuminating the interior of a mailbox. A magnetic switch within the light causes the light to be deactivated when a magnet is in proximity of a portion of the device, and activated when a magnet is not in proximity. The device is removably affixed to the interior of a mailbox and a magnet is affixed to the door of the mailbox in such a manner that when the door is closed the magnet is in close proximity to the device. Closing the door deactivates the device. Opening the door activates the device. The device does not, however, have a method for overriding activation. Unless the magnet is demounted from the door and affixed to the device, the device will remain illuminated as long as the enclosure door is open. This may be acceptable for mailboxes since it is generally not necessary to keep the door open for extended periods of time. This would be unacceptable for many other enclosures.
The methods of non-manual activation, that is, activation by opening of an enclosure, may be divided into two categories: those in which activation occurs by angular tilting of the device, and those in which interaction between the door of the enclosure and the device causes activation. Those activated by angular tilting of the device are suited only to enclosures in which the door hinge is mounted horizontally at the top or bottom of the door. They may be applicable to many tool boxes, fishing tackle boxes and mail boxes, however, when used on a portable enclosure like tool and tackle boxes the light may be activated if the box itself is tipped, thereby draining the battery. Those activated by interaction between the door and the device generally have a movable member which protrudes from the case of the device. Such devices are frequently difficult to seal for the purpose of corrosion prevention, and are prone to sticking if they are left for long periods of time without movement as would be the case, for instance, in a home electrical box. The device described by Brothers has magnetic activation which does not require a protruding movable member and therefore could be constructed in a manner giving resistance to corrosion, although this aspect along with the required features such as gaskets and other sealing means are not addressed in the patent.
The prior art devices previously herein discussed are poorly suited to the illumination of small enclosures such as tool boxes, boxes for fishing tackle, mail boxes, electrical boxes or cabinets in commercial vehicles which may be exposed to humid air or weather. It is desirable that an illumination device for these enclosures be sufficiently small to allow unimpeded use of the enclosure, that the device be resistant to corrosion, that the device have both manual activation and activation by interaction with an enclosure door, and that the device be low cost. It is also desirable that the device be easily demountable and remountable so that the light can be removed from its mount within the enclosure and used to illuminate areas not illuminated by the light when mounted. In some cases it is also desirable that the light be equipped with a means for controlling the field of illumination. None of the prior art devices previously herein discussed has the desired combination of features.
Advances in LED technology and battery technology make possible the construction of devices of small size with high light output and acceptable life for many enclosure lighting applications.
It is accordingly an object of this invention to produce a portable lighting system for enclosures suitable for use in exterior enclosures.
It is also an object of this invention to produce a portable lighting system for enclosures suitable which is suitable for portable enclosures.
It is further an object of this invention to produce a portable lighting system for enclosures which is of a compact size suitable for small enclosures.
It is also an object of this invention to produce a portable lighting system for enclosures which is removably mounted to the interior of the enclosure.
It is also an object of this invention to produce a portable lighting system for enclosures which may be temporarily demounted from the enclosure for use as a hand-held light or removably affixed to, for instance, the bill or brim of a hat, a belt or article of clothing.
It is further an object of this invention to produce a portable lighting system for enclosures which may be activated by interaction between an enclosure door and the light, or by a manually operated switch.
It is additionally an object of this invention to produce a portable lighting system for enclosures which has a means for removably mounting a means for controlling the dispersion of light produced by the device.
It is finally an object of this invention to produce a portable lighting system for enclosures which is low cost.